Forgot to mention that the latest IC date code I found was the 35th week of 1982. One of the floppy drives also has a stamp that reads "3782" which I am guessing refers to the 37th week of 1982. So I'd estimate the date of manufacture to be September 1982. This lines up with the BIOS chip. Any later and it would likely have used the 10/27/82 BIOS.